Morton Code Patch Packing for Point Cloud Compression
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Solution Overview
Problem
Conventional point cloud coding technologies are inefficient due to their reliance on cache-unfriendly Kd-trees for nearest neighbor searches, which hinders effective compression and real-time communication in applications like virtual reality and autonomous driving.
Innovation Solution
The method involves generating patches from point clouds, packing them into images using Morton codes, and smoothing the images to create a video stream, leveraging existing video codecs for efficient compression of geometry, occupancy, and texture data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Kd-trees are used for nearest neighbor searches in conventional point cloud coding, then nearest neighbor search functionality is achieved, but cache efficiency deteriorates and compression effectiveness is reduced
Solution Approach 1:
The patent replaces the conventional Kd-tree data structure with a voxel grid-based approach. Instead of using hierarchical tree structures for nearest neighbor searches, the system divides 3D space into volumetric pixels (voxels) and uses spatial hashing to achieve cache-friendly operations. This substitution of the mechanical search structure resolves the contradiction by eliminating cache misses while maintaining search accuracy.
Solution Approach 2:
The patent segments the point cloud processing into distinct stages: spatial hashing into voxels, patch generation from voxel data, and patch packing into images. This segmentation allows each stage to optimize independently, with the voxel grid providing efficient spatial organization that improves both nearest neighbor search performance and overall compression efficiency.
2Quantity of substance
If conventional point cloud coding is used, then basic compression is achieved, but real-time communication and virtual reality applications are hindered
Solution Approach 1:
The patent implements dynamic patch generation and packing processes that adapt to the specific characteristics of each point cloud frame. The system dynamically adjusts patch sizes, packing configurations, and smoothing parameters based on scene complexity and motion characteristics, enabling real-time processing while maintaining compression efficiency for VR and communication applications.
Solution Approach 2:
The patent performs preliminary spatial hashing and patch generation before the actual compression coding process. By pre-organizing point cloud data into voxels and generating patches in advance, the system reduces computational overhead during real-time transmission, enabling low-latency communication for virtual reality and real-time 3D processing applications.
3Device complexity
If patches are generated and packed into images, then compression is enabled, but reconstruction errors may increase
Solution Approach 1:
The patent incorporates feedback mechanisms where the decoded patches are used to generate updated point cloud representations that are fed back into the smoothing process. This feedback loop allows the system to iteratively refine reconstruction accuracy, correcting errors introduced during patch generation and packing while maintaining manageable algorithmic complexity through the voxel grid framework.
Solution Approach 2:
The patent dynamically adjusts smoothing parameters and patch generation thresholds based on the complexity of the input point cloud and the desired reconstruction accuracy. By adapting parameters such as patch size, smoothing strength, and voxel resolution to match scene characteristics, the system optimizes the balance between compression efficiency and reconstruction fidelity without requiring overly complex algorithms.
Data Source
AI summary
A method and apparatus for encoding/decoding a video stream using video point cloud coding, the encoding/decoding including obtaining an input point cloud, generating patches based on points of the point cloud, packing the patches into an image, generating the video stream based on the image, and smoothing the image using Morton codes.